This invention relates to an electronic musical instrument capable of controlling various tone properties of a musical tone such as the tone color, tone level, tone pitch and tonal effect by control data signals.
In an electronic musical instrument, manual operators are provided for individually setting control data signals representing tone properties such as the tone color, tone level, tone pitch, footage and various tonal effects, and the control data signals are generated in accordance with set states of the respective manual operators. The respective tone properties of the tone signals to be generated by a tone generator are controlled by these control data signals. There has also been known in the art a preset device in which signal states of a set of control data signals corresponding to various tone properties are preset and the preset control data signals are read out collectively by switch means to be utilized for controlling the tone properties. Such preset device is advantageous in that desired signal states of a set of control data signals can be provided collectively so that setting of the respective tone properties can be facilitated. The prior art preset device is not so convenient, however, in a case where it is desired to change only a part of the control data, particularly to change it temporarily. Since the prior art preset device is so constructed that a set of the tone properties are collectively selected from among one or more sets of the tone properties, a partial change in the tone properties can be realized only by preparing newly a set of control data signals representing the respective tone properties including the tone properties in which the desired change has been made. The new preparation of a set of control data signals requires replacement of a read-only memory (ROM) if the read-only memory is employed as a memory device in the preset device whereas it requires rewriting of a random-access memory (RAM) if the random-access memory is employed as the memory device. In any case, such replacement or rewriting is troublesome. On the other hand, in a case where the control data signals are provided in a digital format, there arises a problem that wiring must be saved in sending and receiving these signals.
It is, therefore, an object of the invention to facilitate both setting and modification of the tone properties and realize it with a saved number of wiring. More specifically, it is an object of the invention to facilitate the setting of the tone properties by preparing one or more sets of control data signals representing the respective tone properties and, when a set of control data signals are used in the tone generator, to enable preset signal states of the set of control data signals to be held without being cancelled while enabling only a portion of the control data signals used in the tone generator to be selectively modified or adjusted. It is also a specific object of the invention to realize the delivery of the set of control data signals by a relatively small number of wiring.
The manual operators generally include those for setting the tone level with respect to each tone color, and a tone signal composed of tone colors for the respective manual operators which are mixed together at desired levels is produced by controlling a tone generator in accordance with the set states of the manual operators. The prior art electronic musical instrument has the problem that change in the set level of the manual operator by a relatively large amount causes an abrupt change in the tone signal resulting in occurrence of unpleasant noises such as clicking. Further, in a case where the respective tone properties are controlled by a set of preset control data signals, a relatively large change in the set level occurs when the control data signals are changed to another set of control data signals during performance, resulting in similar occurrence of the noises.
It is, therefore, another object of the present invention to mitigate such abrupt change in the tone properties by gradually and smoothly changing the set value of tone control data for controlling the tone properties such as the tone color, tone level, tone pitch, time and tonal effects when such set value has been changed.